Clinical implications of MR imaging findings in the white matter in very preterm infants: a 2-year follow-up study.
ABSTRACT To explore the association between diffuse excessive high signal intensity (DEHSI), punctate white matter (WM) lesions, and ventricular dilatation around term-equivalent age (TEA) and at clinical follow-up at 2 years in very preterm infants and the effect on neurodevelopment.
Ethical approval for this prospective study was given by the institutional review board, and informed parental consent was obtained. An unselected cohort of 110 preterm infants (gestational age, < 32 weeks) was imaged around or after TEA. Clinical follow-up was performed at a corrected age of 2 years and consisted of a neurologic examination and a mental and developmental assessment (Bayley Scales of Infant Development). Univariate analyses and logistic and linear regression were performed to examine the relationships between variables.
DEHSI was found in 58 of 65 (89%) infants imaged around TEA. DEHSI was never detected in infants imaged after postmenstrual age of 50 weeks and showed no association with neurodevelopmental outcome. Punctate WM lesions and ventricular dilatation were significantly associated with mental (P = .02 for punctate WM lesions) and psychomotor developmental delay (P < .001 and P = .03, respectively), motor delay (P = .002 and P = .02, respectively), and cerebral palsy (P = .01 and P = .03, respectively).
Because of its high incidence in preterm infants around TEA, its absence after a postmenstrual age of 50 weeks, and its association with normal neurologic outcome at a corrected age of 2 years, DEHSI should not be considered part of the spectrum of WM injury, but rather a prematurity-related developmental phenomenon.
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ABSTRACT: To define magnetic resonance imaging (MRI) appearances of the brain in extremely preterm infants between birth and term, a sequential cohort of infants born at a gestational age <30 weeks was studied with a dedicated neonatal magnetic resonance scanner. Images of infants (n = 41) with a median gestational age of 27 weeks (range 23 to 29 weeks) were initially obtained at a median age of 2 days (range 1 to 20 days) and then repeatedly studied; 29 (71%) infants had MRI at a median gestational age of 43 weeks (range 38 to 52 weeks) (term MRI). On the initial MRI scan 28 of 41 infants had abnormalities: either intraventricular hemorrhage, germinal layer hemorrhage, ventricular dilatation, or diffuse and excessive high signal intensity in the white matter on T(2)-weighted images. When magnetic resonance images for preterm infants at term gestation were compared with those of infants in the control group born at term, 22 of 29 infants had dilatation of the lateral ventricles, 24 of 29 had squaring of the anterior or posterior horns of the lateral ventricles, 11 of 29 had a widened interhemispheric fissure or extracerebral space, and 22 of 29 had diffuse and excessive high signal intensity in the white matter. There were no cases of cystic periventricular leukomalacia. We conclude that MRI abnormalities are commonly seen in the brain of preterm infants on whom images are obtained within 48 hours of birth and that further abnormalities develop between birth and term. A characteristic appearance of diffuse and excessive high signal intensity in the white matter on T(2)-weighted images is associated with the development of cerebral atrophy and may be a sign of white matter disease. These MRI appearances may help account for the high incidence of neurodevelopmental impairment in extremely preterm infants.Journal of Pediatrics 09/1999; 135(3):351-7. · 4.04 Impact Factor
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ABSTRACT: MR imaging can now be used safely in extremely preterm infants. The aim of this study was to compare the MR imaging appearance of the immature brain with neuropathologic findings at postmortem examination. Seven extremely sick preterm infants, born at a median of 24 weeks' gestation, were studied using T1- and T2-weighted MR sequences. Infants died at a median of 3 days after initial MR imaging, and postmortem examinations were carried out. The cortex and germinal matrix were seen as areas of low signal intensity on T2-weighted images, which corresponded to their highly cellular histologic appearance. The periventricular and subcortical layers of white matter had a high signal intensity, corresponding to high fiber and relatively low cellular density; the intermediate layer of low signal intensity corresponded to a dense band of migrating cells. Regions of acute hemorrhage were seen as low signal intensity and regions of infarction as high signal intensity on T2-weighted images. One infant with mild periventricular leukomalacia had some low signal intensity on T1-weighted images, but no focal changes on T2-weighted images. Regions of neuronal mineralization, seen in association with infarction and capillary proliferation, within the basal ganglia and thalami were characterized by very low signal intensity on T2-weighted images and by very high signal intensity on T1-weighted images. There were no imaging abnormalities detected in regions with more subtle histologic abnormalities, such as increased glial or apoptotic cells. MR imaging can be used to observe normal developing brain anatomy in extremely premature infants; it can detect areas of hemorrhage and infarction within the developing brain, but conventional MR imaging may not detect more subtle histologic abnormalities.American Journal of Neuroradiology 09/1999; 20(7):1349-57. · 3.17 Impact Factor
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ABSTRACT: Development of gross motor function in children with cerebral palsy (CP) has not been documented. The purposes of this study were to examine a model of gross motor function in children with CP and to apply the model to construct gross motor function curves for each of the 5 levels of the Gross Motor Function Classification System (GMFCS). A stratified sample of 586 children with CP, 1 to 12 years of age, who reside in Ontario, Canada, and are known to rehabilitation centers participated. Subjects were classified using the GMFCS, and gross motor function was measured with the Gross Motor Function Measure (GMFM). Four models were examined to construct curves that described the nonlinear relationship between age and gross motor function. The model in which both the limit parameter (maximum GMFM score) and the rate parameter (rate at which the maximum GMFM score is approached) vary for each GMFCS level explained 83% of the variation in GMFM scores. The predicted maximum GMFM scores differed among the 5 curves (level I=96.8, level II=89.3, level III=61.3, level IV=36.1, and level V=12.9). The rate at which children at level II approached their maximum GMFM score was slower than the rates for levels I and III. The correlation between GMFCS levels and GMFM scores was (.91. Logistic regression, used to estimate the probability that children with CP are able to achieve gross motor milestones based on their GMFM total scores, suggests that distinctions between GMFCS levels are clinically meaningful. Classification of children with CP based on functional abilities and limitations is predictive of gross motor function, whereas age alone is a poor predictor. Evaluation of gross motor function of children with CP by comparison with children of the same age and GMFCS level has implications for decision making and interpretation of intervention outcomes.Physical Therapy 11/2000; 80(10):974-85. · 2.78 Impact Factor